No, it's not the zoo's celebrity panda cubs—it's a pair of Sumatran tiger cubs named Bandar and Sukacita. The cubs made their public debut on Wednesday with a swimming test. (Also see "Sumatra's Last Tigers.")

The test? See if the cubs could tread water and climb ashore.

Swim to Shore

Bandar, the male cub, was first in line. After being tossed in the water, he climbed ashore and ran around a bit before being caught by zookeepers.

Sukacita, his sister, took two tries getting onshore, after which she let out a little roar of achievement.

The cubs passed the test, allowing them to move in with their proud parents, mom Damai and dad Kavi.

Being able to swim is a crucial test for the 13-week-old cubs, whose habitat is encircled by water. The swim reliability test at the zoo's Great Cats exhibit had zookeepers on hand to ensure the safety of the siblings and guide them to shore.

Sumatran tigers are endangered, and the birth of the cubs in August was considered "a conservation success," according to the National Zoo's website. With only about 500 Sumatran tigers living in the wild, Bandar and Sukacita represent the future of the species.